1. Field of the Invention
The present invention relates to an image reading device capable of reading an image-bearing original in accordance with image processing conditions prescribed for each original, and also relates to a method for prescribing image processing conditions such that a plurality of originals from an original cassette are identified and read into image signals individually.
2. Description of the Related Art
According to an image reading device of recent use in the prepress printing industry, an original, such as a color document, is read into image signals with a photoelectric element; then the image signals are processed in a predetermined way. More specifically, the image reading device reads the original with a flatbed-scanning type scanner or a drum-scanning type scanner. With the drum-scanning type scanner, the original is pasted on a scanner drum. After that, the drum is rotated and the original is read into the image signals. With the flatbed-scanning type scanner, the original is inserted into a flatbed-type cassette. After that, the flatbed-type cassette and a photographic element such as CCD (Charge Coupled Device) are displaced relatively and the original is read into the image signals.
To improve efficiency, a recent flatbed-scanning type scanner employs a stacker wherein a plurality of original cassettes are loaded, and they are delivered successively by an automatic cassette feeding device. Thus, the original cassettes accommodating an original are delivered to the image reading device one after the other. Subsequently, the image reading device processes the original according to prescribed image processing conditions.
For example, according to an image reading device in U.S. Pat. No. 5,050,007, image processing conditions relating to an original are stored in an internal storage. When an original cassette is delivered to a reading unit, the operator identifies the original at the original cassette, then selects and designates the image processing conditions relating to the identified original. The original is read according to the image processing conditions.
With an image reading device as in U.S. Pat. No. 5,073,829, one original is inserted into each original cassette; and each original cassette has an identification code. Prior to a regular scanning, every original goes through a tentative scanning (pre-scanning) and image processing conditions obtained by the pre-scanning is stored with an identification code of the original (or the identification code of the original cassette). Subsequently, when the original cassette is delivered to an image reading unit of the image reading device by an automatic cassette feeding device, an original identification code reading unit reads the identification code of the original cassette. Thus, the delivered original cassette is recognized by the identification code, whereby the original in the original cassette is identified. Subsequently, the image reading device detects the image processing conditions which correspond to the identification code of the original and reads the original according to the detected image processing condition.
Further improvement in efficiency and automation are demanded for the image reading device with the automatic original feeding device. Specifically, it would be more economical and efficient if more than two originals could be inserted into each original cassette so that a stacker could accommodate a larger number of papers. Further, a rapid feed/discharge of the original cassette would be desirable.
To insert a plurality of originals into one original cassette, the originals must be identified individually and image processing conditions must be set for each original, since processing of the original rather than processing of the original cassette has been generally controlled in the prepress processing industry.
The conventional image reading device, however, operates on the assumption that each original cassette accommodates only one original; and the image processing conditions which relate to each original are detected in accordance with the identification code of the original cassette. Therefore, if a plurality of originals were inserted into one original cassette, the conventional image reading device would fail to identify the originals individually, and set the image processing conditions for each original.